Logical Reasoning

PT108 · S2 · Q9 Very powerful volcanic eruptions send

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Very powerful volcanic eruptions send large amounts of ash high into the atmosphere, blocking sunlight and causing abnormally cold temperatures for a year or more after the eruption.

Conclusion

If the summer frosts / dimmed sunlight in China that occurred in the year following the eruption of Mount Etna were caused by volcanic ash in the atmosphere, then Mt. Etna's erupted ash must have spread over great distances.

Evidence

China is thousands of miles east of Sicily.

Evaluate

This conclusion is a conditional claim, so if we want to argue with it, we have to remind ourselves what it means to argue with or Refute a Conditional.

Arguing with a conditional is saying, .

So in this case, we want to think about how we might argue that 1. the summer frost and dim sun in China was caused by volcanic ash in the atmosphere but 2. the ash sent into the atmosphere by Mt. Etna did not spread over great distances.

In order to reconcile those two, we'd either need to argue that ash doesn't have to spread all the way from Italy over to China in order for a volcano in Italy to affect China's climate.

Or we could argue that there was volcanic ash in the atmosphere from a source besides Mt. Etna.

Goal

Look for an answer asking, or one asking

In evaluating the support given for the conclusion advanced in the last sentence of the passage, it would be most important to determine whether

modern monitoring equipment can detect
No Impact
Whether modern monitoring equipment can / can't do a certain thing has nothing to do with evaluating whether it was the case 2000+ years ago that ash from Italy spread to China and caused the cold summer.
4% picked this
the abnormal weather in China
No Impact: duration of weird weather
Whether the abnormal weather in China lasted a full year or only 10 months doesn't help us ascertain whether or not the abnormal weather in China was caused by ash spreading over great distances from Italy.
10% picked this
temperatures in Sicily were abnormally
No Impact
We fully expect Sicily to have been abnormally cold after the eruption, because it's right underneath the ash cloud of Mt. Etna, so much sunlight will be blocked. If temperatures weren't that cold after the eruption, that would seem to mean it wasn't that bad an eruption or that the ash from the eruption quickly dispersed from the area around Sicily, or that Sicily was going through an abnormal heat spell around the time of the eruption so the cooling from the eruption only brought the temperature down to a normal amount. It doesn't seem to tell us anything with any direct impact on the cold Chinese summer.
7% picked this
Correct
there were any volcanic eruptions
Why this is right
This provides us with a potential way to weaken the conclusion. To weaken the conclusion we need to figure out how the trigger could be true while the outcome is false. How could it be that "the cold Chinese summer was caused by volcanic ash in the atmosphere" (it doesn't specify where the volcanic ash came from), but that the ash from Mt. Etna did not spread over great distances from Italy to China? We could say that the cold Chinese summer was caused by volcanic ash in the atmosphere from an eruption nearer to China!
Skill tested: Evaluate · how this choice captures the argument's function is the move to repeat next time.
78% picked this
subsequent eruptions of Mount Etna
No Impact: subsequent eruptions
Whether other eruptions in the proceeding 2000+ years were as strong or weren't as strong does nothing for our efforts to solve the causal mystery of what was causing the cold Chinese summer of 43 B.C.
1% picked this

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